The invention relates to a conveyor device or conveying apparatus pursuant to the introductory portion of claim 1.
Such conveying apparatus have been known for some time. They are provided, as essential elements, with an extruder and a gear pump that is connected to the extruder, either directly or indirectly; the gear pumps are frequently embodied as planetary pumps. Due to the effect of the extruder, a very high conveying capacity can be provided for, and the planetary pump enables the realization of a high and also uniform output pressure.
If polymeric material such as rubber or the like is to be conveyed with the conveying apparatus, it is essential that the material that is to be conveyed be homogenized. Frequently, at least portions of the material are still cold or highly viscous. However, it is just such cold islands that tend to remain inhomogeneous, since they practically do not intermix with the remaining material. To compensate for this, it is known to equip the extruder with a so-called transfer mix zone, where the extruded material is better intermixed, but at the cost or sacrifice of the conveying capacity.
Furthermore, various measures have been proposed to improve the intermixing with a combination of an extruder and a gear pump. For example, with the approach of U.S. Pat. No. 4,642,040, an inclined channel is provided between extruder and gear pump. A further solution is disclosed in DE-PS 103 48 985. With this gear pump, a transfer mix zone having a thread depth that increases toward the gear pump is provided. Although this approach permits a relatively good conveying capacity at high pressure, it would nonetheless be desirable to further improve the mixture even with different starting materials.
It is therefore an object of the present invention to provide a conveying apparatus with which can be expected and improved throughput at high pressure even with starting materials that are different and are present in an inhomogeneous state.